Ion implanters

Abstract

The present invention relates to components in ion implanters having surfaces, such as graphite surfaces, adjacent to the path of the ion beam through the ion implanter. Such surfaces will be prone to sputtering, and sputtered material may become entrained in the ion beam. The present invention sees the use of surfaces that are formed so as to present a series of angled faces that meet at sharp intersections. In this way, any material will be sputtered away from the ion beam.

1. An ion implanter component having a surface that defines, at least in part an ion beam path through an ion implanter, wherein at least a portion of the surface is shaped so as to present a series of angled faces and upright faces that meet at sharp intersections, thereby forming a substantially saw tooth cross section, and wherein the angled faces above a center plane are arranged to face upwardly and away from the ion beam path passing the surface, and the angled faces below the center plane are angled to face downwardly and away from the ion beam path. 
     
     
       2. The component of  claim 1 , wherein the component defines the ion beam path therethrough and wherein portions of all surfaces immediately adjacent the ion beam path are shaped so as to present a series of angled faces that meet at sharp intersections, thereby forming a substantially saw tooth cross section, such that the angled faces are arranged to face away from the ion beam path through the component. 
     
     
       3. The component of  claim 1 , wherein the angled faces comprise a series of grooves. 
     
     
       4. The component of  claim 3 , wherein the grooves extend generally in the direction of the ion beam path through the component. 
     
     
       5. The component of  claim 3 , wherein the grooves have a width selected from the group of: 10 mm to 100 mm, 10 mm to 50 mm, and 10 mm to 25 mm. 
     
     
       6. The component of  claim 1 , wherein the component is formed of graphite. 
     
     
       7. The component of  claim 6 , comprising a surface coating having a greater resistance to sputtering than graphite. 
     
     
       8. The component of  claim 7 , wherein the coating is tungsten or tantalum carbide. 
     
     
       9. The component of  claim 1 , wherein one or more of the faces has been roughened to provide a pattern of surface features. 
     
     
       10. The component of  claim 9 , wherein the surface features comprises an array of tetrahedra. 
     
     
       11. The component of  claim 1 , wherein the component is a flight tube. 
     
     
       12. The component of  claim 1 , wherein the component is an element defining a beamline aperture. 
     
     
       13. A mass analyzer for an ion implanter comprising one or more parts having a surface that define a flight tube for a path of a beam of ions passing through the mass analyzer, wherein at least a part of the surface defining the flight tube is shaped so as to present a series of faces that are angled away from the ion beam path, and wherein the series of faces meet at sharp intersections, thereby forming a substantially saw tooth cross section, the angled faces above a center plane of the surface being angled to face upwardly and away from the ion beam path, and the angled faces below the center plane being angled to face downwardly and away from the ion beam path. 
     
     
       14. The mass analyzer of  claim 13 , wherein the series of faces form a series of grooves extending generally in the direction of the ion beam path. 
     
     
       15. The mass analyzer of  claim 14 , wherein the grooves have a width selected from the group of: 10 mm to 100 mm, 10 mm to 50 mm, and 10 mm to 25 mm. 
     
     
       16. The mass analyzer of  claim 14 , wherein the one or more parts are formed of graphite and comprise a surface coating having a greater resistance to sputtering than graphite. 
     
     
       17. The mass analyzer of  claim 16 , wherein the coating is tungsten or tantalum carbide. 
     
     
       18. The mass analyzer of  claim 17 , wherein the surface having the surface patterning is oriented to face up the flight tube in an upstream direction.